A competition is being held in Zawame City between Armored Riders Gaim, Ryugen, Baron, Kurokage, and Gridon with a batch of Lockseeds from DJ Sagara as a prize when a Crack opens amid the battle and the Pitcher Plant Inhumanoid appears from it, attacking Mai. Gaim, Ryugen, and Baron protect Mai and pursue the Inhumanoid as it retreats through the Crack. The Riders arrive in an alternate reality where the inhabitants run away in fear from Gaim, mistaking him for someone else. Looking for answers, they join a battle with a Kamen Rider resembling OOO, while Takatora learns of the situation and follows after the other Armored Riders. Kaito breaks into a burning castle and meets Nobunaga, who entrusts him with a Core Medal before dying amid the flames, but he manages to save Ranmaru from the fire. Outside, the red Kamen Rider Gaim appears and defeats Kamen Rider OOO, before having him absorbed by the Pitcher Plant Inhumanoid. Kouta and Mitsuzane flee the scene just to be later captured by an alternate Iyeasu Tokugawa, who reveals that in that reality each of the Heisei Riders are Bujin Riders serving a feudal warlord and fighting to unify the country but most of them have been defeated, including his own Bujin Wizard, by the red-colored Kamen Rider Bujin Gaim, who serves no one except for himself.